Abstract
In this essay I will embark on the venture of changing the realist reader’s mind about the informational viewpoint for physics: “It from Bit”. I will try to convince him of the amazing theoretical power of such paradigm. Contrary to the common belief, the whole history of physics is indeed a winding road making the notion of “physical object”–the “It”–fade away. Such primary concept, on which the structure of contemporary theoretical physics is still grounded, is no longer logically tenable. The thesis I advocate here is that the “It” is emergent from pure information, an information of special kind: quantum. The paradigm then becomes: “It from Qubit”. Quantum fields, particles, space-time and relativity simply emerge from countably infinitely many quantum systems in interaction. Don’t think that, however, I can cheat by suitably programming a “simulation” of what we see. On the contrary: the quantum software is constrained by very strict rules of topological nature, which minimize the algorithmic complexity. These are locality, unitariety, homogeneity, and isotropy of the processing, with minimal quantum dimension. What is amazing is that from just such simple rules, and without using relativity, we obtain the Dirac field dynamics as emergent.
Giacomo Mauro D\'Ariano